(TheDrinksBusiness) - The world’s five biggest auction houses have reported a 25% slump during the first half of 2012 as investors adopted a cautious approach to the big names and Chinese buyers shifted their focus towards Burgundy. Despite upbeat reports from many houses, Bloomberg reported that the big five – Acker Merrall & Condit, Zachys, Christie’s, Sotheby’s and Hart Davis Hart – saw wine sales slip to £160 million during the first six months of 2012.